The experiment at high altitude was carried out by Florin Périer, Pascal's brother-in-law, on 19 September 1648, as an extension of Torricelli's experiments at low altitude in 1643. See Peter Dear, 'Miracles, experiments and the ordinary course of nature', Isis, 1990, 81: 663-683, esp. pp. 676-683. This painting is one of over 26 paintings by the historical painter Ernest Board that were commissioned by Henry S. Wellcome in around 1912 of episodes relating to the history of medicine and science.